Question 21
Suppose $a,$ $b,$ and $c$ are nonzero real numbers, and $a+b+c=0.$ What are the possible value(s) for $$
\dfrac{a}{|a|}+\dfrac{b}{|b|}+\dfrac{c}{|c|}+\dfrac{abc}{|abc|}?
$$
\dfrac{a}{|a|}+\dfrac{b}{|b|}+\dfrac{c}{|c|}+\dfrac{abc}{|abc|}?
$$